Synthesis and characterization of new optically active poly(acrylamide/methacrylurea-co-vinyl acetate) copolymers with dansyl units

Abstract

Novel optically active copolyacrylates synthesized by conventional radical polymerization of R/S-(+/−)-α-ethylbenzylacrylamide (R/S-EBzA) or R/S-(+/−)N-methacryloyloxyehtyl-N′-α-ethylbenzyl(urea) (R/S-MEBzU) and the vinyl acetate (VAc) in the presence of 1,1′-azobis (cyclohexanecarbonitrile) as the initiator showed optical rotation values ([α]D23) of +45°/−50° for R/S-EBzA-co-VAc and of −40° in the case of S-MEBzU-co-VAc. Next, the hydrolysis reaction of the synthesized copolymers was accompanied of their chemical modification with dansyl chloride in order to obtain novel photopolymers. The structure, some physical and chemical properties of these polymers were investigated through spectral and thermal analysis (1H-NMR, FTIR, UV/vis and fluorescence, and DSC), gel permeation chromatography, and optical measurements. The sensing capacity of the above photopolymers was examined by fluorescence spectroscopy in parallel with quenching studies using various acids (1-S-camphorsulfonic acid, p-toluenesulfonic acid, HCl) and metal ions (Cu2+, Hg2+, Fe2+). The results revealed that the dansyl fluorophore could be useful in sensor applications for detection of some metal ions and in monitoring the protons in organic medium, the most efficient quencher being Fe2+ and HCl for all dansyl-labeled polyacrylates.